1. Field of the Invention
This invention relates to the fermentative production of L-lysine. More particularly, it relates to a fermentation process for producing L-lysine by using a microorganism belonging to the genus Brevibacterium or Corynebacterium.
2. Discussion of the Background
A large number of methods have been proposed for producing L-lysine by fermentation processes. These include: the method of using strains resistant to S-(2-aminoethyl)-1-cysteine (hereinafter abbreviated as AEC) disclosed by Japanese Patent Publication No. 55213 (1967); the method of using mutant strains which are resistant to AEC, and are L-leucineless, L-homoserineless, L-prolineless, L-arginineless or L-alanineless (hereinafter referred to as Ala.sup.-) disclosed by Japanese Patent Application Laid-open No. 36888 (1974), No. 80289 (1974) and No. 21078 (1976); the method of using mutant strains resistant to AEC and leucine analogues, such as .beta.-hydroxyleucine (hereinafter abbreviated as HL) disclosed by Japanese Patent Publication No. 1833 (1978); the method of using mutant strains resistant to .alpha.-chlorocaprolactam (hereinafter abbreviated as CCL) disclosed by Japanese Patent Publication No. 43591 (1978); the method of using .gamma.-methyllysine (hereinafter abbreviated as ML) disclosed by Japanese Patent Publication No. 19235 (1981); the method of using strains sensitive to fluoropyruvic acid (hereinafter abbreviated as FP) disclosed by Japanese Patent Application Laid-open No. 9783 (1980); and the method of using mutant strains with lowered pyruvic acid kinase activity disclosed by Japanese Patent Application Laid-open No. 170487 (1983).
All of these fermentative processes for producing L-lysine are expensive, making the L-lysine itself expensive. In view of the considerable demand on L-lysine there is therefore a strongly felt need for a more economical process for the production of L-lysine.